The role of autoanti-idiotypic immunity in the regulation of immune resonses in animal models of human diseases will be studied. Experimental autoimmune myathenia gravis will be produced in C57B1/6 mice by injection of purified acetylcholine receptor prepared from Torpedo californica and purified by means of the neurotoxin isolated from the cobra Naja naja siamensis. The disease will be assessed by clinical, pharmacologic, neurophysiologic, and histologic parameters. Idiotype directed against the acetycholine receptor will be obtained from immunoblasts separated by velocity sedimentation from non-stimulated cells. The effect of autoanti-idiotypic immunity on the development of the disease and on the course of the disease once o developed will be assessed and compared with measured immunologic responses in the animals to the acetycholine receptor. Ovalbumin will be used to immunize C57Bl/6 mice and immunoblasts prepared from spleens from such animals stimulated by antigen will be a source of idiotype used to immunize further members of this strain to determine the effect of autoanti-idiotypic immunity, specifically on the development of IgE responses to minimal doses of antigen. Animals previously immunized with minimal doses of ovalbumin will be used to study the effects of autoanti-idiotypic sensitization upon the ongoing immune response. Patients will be bled prior to and during a course of immunotherapy for ragweed hayfever to obtain sufficient amounts of serum to determine whether the appearance of autoanti-idiotypic antibodies correlates with the effects of immunotherapy.